Working hypothesis and aims: Biotin is conjugated covalently to several proteins and use as a co-factor. Conjugation of biotin to non-targeted, unspecific proteins (e.g. immunoglobulins) leads to the breakage of the immune tolerance and to the formation of anti-biotin antibodies. Anti-biotin antibodies will be found in correlation with the progression and the present of autoimmune disease. In this research the correlation between immune response against biotin and the formations of autoimmune disease, will be studied: